1. Field of the Invention
The present invention relates generally to a semiconductor processing tool and, more specifically, to a thermal processing tool having dielectric barrier discharge lamp assembly.
2. Description of the Related Art
Rapid thermal processing (RTP) is a process for annealing substrates during semiconductor fabrication. During this process, thermal radiation is used to rapidly heat a substrate in a controlled environment to a temperature of up to and beyond nine hundred degrees Celsius. This temperature is maintained for a specific amount of time ranging from less than one second to several minutes, depending on the process. The substrate is then cooled before further processing.
Conventionally, RTP chambers typically include radiant heat sources or lamps, a chamber body and a substrate support assembly. The substrate support assembly is disposed in the chamber body and supports a substrate while processing. The radiant heat sources are typically mounted to a top surface of the chamber body or embedded in the interior walls of the chamber so that the radiant energy generated by the sources impinge upon the substrate positioned on the substrate support assembly. A quartz window is typically disposed in the top surface of the chamber to isolate radiant heat sources and the interior process region where the substrate typically disposes in the process chamber.
The radiant energy generated by the lamp is in the form of a wave of thermal radiation. The radiation is broadband and typically has a peak wavelength of around 800 nm to around 1500 nm. During transmission through the quartz window to the substrate surface, a portion of the radiant energy may be lost. For example, wavelengths longer than about 4000 nm are not transmitted. The quartz window thus causes a change in wavelength of the radiation energy passing therethrough, which now may be between about 400 nm to about 4000 nm, or even higher, and into the infrared region (IR). These wavelengths of radiant energy are insufficient to drive photochemical reactions on the substrate surface and may further result in an insufficient number of generated reactive species being available to react and form a bulk film on the substrate.
Therefore, there is a need for an improved lamp assembly for use in a thermal processing chamber.